Synchronize two CalDAV servers

Question

In short, I'm looking for a solution on Ubuntu/Linux that will allow me to keep two calendars, each managed by a remote CalDAV server with a web interface, in sync, in the sense that any change I make on one of calendars through its web interface would be propagated, with minimal delay, to the other. Each of the web interfaces allows me to subscribe to remote calendars, but the subscriptions are unfortunately read-only, so that doesn't help.

I've looked at a few approaches already, but haven't found anything satisfactory. The most promising seemed to be syncevolution, which could be used to synchronize the remote calendars with local databases, but it wasn't clear whether I could (1) sync them both to a single local database or (2) sync them to separate local databases but keep these local databases in sync somehow. One of these would be required to do what I want.

Is there a way to achieve my aim here?

Answer 1

This question has now been answered on the SyncEvolution mailing list. Short summary: yes, SyncEvolution can be configured to do this kind of job, but it relies on newer features that have not been well documented. The linked thread contains specific configuration instructions. In a few days, I'll edit this answer to include my experiences setting it up.

Answer 2

I'm not sure why Markus' answer wasn't converted to an answer, but I can confirm that vdirsyncer will do this.

If it is still true that gContacts doesn't work, that is because Google's implementation is completely borked - and that wasn't in the question in the first place anyway.